Preparation Of Graphene By KOH-assisted Catalytic Microwave Pyrolysis Of Waste Tire

The booming global automotive industry has spawned a large number of abandoned car tires.Conventional landfilling and incineration not only generate secondary pollutants,but also easily cause resource waste.Waste tires are carbon rich rubber waste,and extracting and converting the carbon from tires into high value-added graphene materials is a potential method for recycling waste tires.However,the traditional method of preparing graphene from pyrolysis waste tires not only requires long-term high-temperature graphitization pretreatment,but also cumbersome subsequent processing.This article uses strong alkali assisted catalytic microwave pyrolysis of waste tires to prepare graphene.The microwave dielectric properties of waste tires are studied in detail,and the laws of strong alkali assisted catalytic microwave pyrolysis to prepare graphene are explored.The mechanism of strong alkali assisted catalytic microwave pyrolysis to prepare graphene is revealed,laying a theoretical foundation for the resource recovery of waste tires.(1)Research on the dielectric properties of waste tires.The dielectric properties of waste tires show a trend of increasing with the increase of apparent density between0.40 g/cm~3 and 0.72 g/cm~3.After adding strong alkali to waste tires,the dielectric properties of the mixture also increase with the increase of KOH mass ratio.During the process of heating the mixed material to 750℃,the continuous changes in dielectric properties express the escape of pyrolysis gas from the tire.After 750℃,its dielectric constant reaches around 30,and then remains unchanged with the increase of temperature.(2)Study on Preparation of Graphene from Waste Tires by Strong Alkali Assisted Catalytic Microwave Pyrolysis.As the temperature increases,the degree of graphitization of graphene increases,the pore size increases,and prolonging the insulation time also helps to separate impurities from graphene.The temperature for preparing graphene using this method must be higher than 1000℃and kept for at least4 hours.In addition,as the amount of alkali increases,the reaction process becomes faster and the defects of graphene become higher.(3)Research on the Mechanism of Strong Alkali Assisted Catalytic Pyrolysis of Waste Tires.In the process of strong alkali assisted catalytic microwave pyrolysis of waste tires,the mass loss of the product is close to 55%.When heated to 750℃by microwave,the waste tire reacts with KOH to release H2.At the same time,the waste tire is decomposed into small carbon flakes and catalytic reconstituted into defective graphene.After a period of insulation,impurities such as K detach from graphene,increasing the formability of graphene and obtaining high-quality graphene as the cornerstone of waste tire.